Telephone system



April l, 1941.

o. CESAREO ETAL 2.236.499

TELEPHONE SYSTEM Filed Nov. l5, 19259 2 Shee's--SheetI 1 o. CESAREO"WENTOR' RoR/PPE@ B www4@ A TTOR/VEV April 1, 1941. o. cEsAREo ErAL2,236,499

TLPHONE SYSTEM v l Filed Nov. 15, 1959 2 sheets-sheet z ooaoooooo o oIIHIH A 1 rom/5 Patented Apr. 1, 1941 UNITED STATES PATENT OFFICETELEPHONE SYSTEM poration of New York Application November 15, 1939,Serial No. 304,480

6. Claims. (Cl. 179-16) This invention relates to the transmission ofimpulses and particularly to impulse repeaters used in telephonesystems.

The object of the invention is to obtain a greater degree of reliabilityin the operation of' impulse repeaters.

For some purposes it is desirable to use an impulse repeater in whicheach series of impulses is momentarily stored or registered and is thenretransmitted. Usually the incoming series of impulses is registered ona stepping switch which advances and marks a terminal corresponding tothe number of impulses, and the number of outgoing impulses is countedby a counting switch which steps over its terminals' until it reachesthe position marked by the register switch.

According to the present invention the positions to which theregistering switch is advanced in response to the successive incomingseries of impulses are marked by space-discharge tubes to measure theextent of the corresponding movements of the counting switch indetermining the transmission of the outgoing impulse series. Oneadvantage secured by the use of these tubes is that the register switch,having operated the proper tube to mark a position, is free to resumeits forward movement at once in response to the next series of impulses.As the counting switch reaches the marked position its movement isarrested by the presence of the operated tube, and the tube isautomatically restored toits normal condition. Another advantage in theuse of tubes for marking the positions selected by the register switchis that the marking is positive and remains effective until it isencountered subsequently by the counting switch. That the marking, onceestablished, should remain permanently eiiective until detected by thecounting switch is important in the operation of repeaters of this kind,since the counting switch in its movement to control the outgoingimpulses may lag considerably behind the register switch, whichcontinues to advance in response to the incoming impulse series.

In the drawings accompanying the detailed specication Figs. 1 and 2illustrate diagrammatically an automatic telephone system and disclosein detail one embodiment of an impulse repeater incorporating thefeatures of this invention.

The repeater is shown at the incoming end of a trunk T interconnectingan originating automatic olce with a terminating automatic loilce. Theoriginating office includes a line-lnder switch F and a selector S bymeans of which the calling line I is extended over the trunk T to thetermi- 'nating office. The outgoing end of the trunk T may also beprovided with an impulse repeater or with the usual trunk controlcircuit 2.

The incoming impulse repeater in the terminating oice is interposedbetween the incoming conductors of the trunk T and the first selector lswitch S-L 'I'he selector switch S-I has access through succeedingselectors, such as selector S-Z, and through connector switch C tocalled subscribers lines, such as the line 3. The finder switch F, theselectors S,.S-I and S-Z, and the connector switch C may be of anywell-known type, such as those generally employed in stepby-stepsystems. I

The incoming impulse repeater includes an impulse receiving relay 4,which responds to the impulses transmitted from the calling subscribersdial 5. The repeater also includes a register switch S-3 and a countingswitch S-4. These switches may be of the well-known step-by-step type inwhich the brushes have no normal position. Each switch is provided withfour brushes and associated arcuate terminal banks and with a steppingmagnet. The banks and brushes of each switch are arranged in pairs, thebrushes of each ,pair being positioned on the driving shaft degreesapart so that one brush enters its bank of associated terminals as soonas the other brush of the pair leaves the last terminalof its bank.There are two such pairs in each of the switches; brushes 6 and 'I andbrushes 8 and 9, respectivelyLbeing paired in the switch S--3, and

' brushes I0 and II and brushes I2 and I3, respectively, being paired inthe switch S-4. The stepping magnets I4 and I5 serve respectively tostep the brushes of the switches S-3 and S-4, these magnets beingarranged to advance the brushes upon deenergization of their coils.

The positions assumed by the brushes 6 and l of the register switch S-3are marked by spacedischarge tubes. An individual tube is provided foreach terminal position of the brushes 6 and l. These tubes, which may beof any suitable construction, such as the well-known three-elementgas-lled type, have their control electrodes connected to the respectiveterminals in the -switch banks. The anodes of the tubes are connectedtothe corresponding positional terminals in the banks associated withbrushes I0 and II of the counting switch S--4. Also the anodesareconnected to the sustaining battery through suitable resistanceelements. The cathode elements of ving impulses.

register switch S-3 until it reaches'the position marked by thedischarged tube. Thereupon the counting switch comes to rest'and,terminates the transmission of the outgoing impulse series. Dependingupon the speed with which the calling party manipulates his dial foreach succeeding digit, the counting switch S-4 may orl may not reach themarked position before the register switch S-3 moves away from thatposition in response to the next succeeding series of incom- Each tubethat is fired to mark a terminal position is automatically quenched assoon as the marked position has been reached by the counting switch.

A detailed description will now be given of the' operation of thesystem. For this purpose it will be assumed that the subscriber of lineI in the originating ofce wishes to converse with the subscriber of line3 in the terminating oiiice. It will also be assumed that the directorynumber of the called line 3 is 9913 and that the register and countingswitches S-3 and S--4 of the repeater are standing in position 3 asindicated by their brushes.

The calling subscriber initiates the call in the usual manner andoperates the selector switch S by means of his dial to seize an idleoutgoing trunk T extending to the desired called oilice. The trunkcontrol circuit 2 applies the usual guarding potential to the testterminal in the selector S and closes the conductors of trunk T toVoperate the impulse relay 4 of the incoming repeater. The operatingcircuit of relay 4 may be r traced from battery through the upperwinding of the relay, normal contacts of reversing relay I6, lower leftwinding of repeating coil I1, trunk conductor I8, thence over the loopand returning over trunk conductor I9 through the upper left winding ofcoil I1 and the normal contacts of relay I6 and the lower winding ofrelay 4 to ground.

Relay 4 closes an obvious operating circuit for slow-release relay 20.Relay 2D closes a short circuit around the winding of relay 2|. Relay 2|and slow-release relay 22 are normally in an energized condition whenthe switches S-3 and S-4 are standing in the same position. Theenergizing circuit for these relays may be traced from battery throughthe winding of slow-release relay 23, normally closed contacts of 20,conductor 24, brush I2, brush 8, conductor 25 through the windings ofrelays 22 and 2| to ground. Relay 23, however, is marginal and does notoperate in series with the resistance of relay 2|. The operation ofrelay 20, therefore, as above noted, closes a short circuit around thewinding of relay 2|, whereupon relay 2| releases. Relay 20 also opensthe circuit above traced for relays 23 and 22.

Relay 2B in operating also closes a circuit from ground over conductor28 through resistance 29, winding and normal contacts of relay 30 tobattery at the left contacts of the pulsing relay 21. Relay 30 operatesand locks directly to battery through its lower front contact. Relay 30atits'f'sl upper contact closes the pulsing loop extending to thesucceeding switch S-I. This pulsing circuit may be traced from conductor3| to the upper right winding of repeating coil I1, winding of polarizedsupervisory relay 32, lower right winding of coil I1, upper contacts ofrelay 30 to conductor 33. The closure of this circuit prepares theswitch S-I for receiving the next series oi impulses. Relay 30 alsocloses a circuit from battery through the winding of relay 23, Contactof relay 30, thence over conductor 24, brushes I2 and 8, conductor 25,winding of relay 22 to ground at relay 2U. Relay 23 operates and relay22 holds in this circuit, relay 2| remaining deenergized. Relay 23closes an operating circuit of slow-release relay 26 traceable frombattery through the winding of the latter relay, front contact of relay23to ground at the iront contact of relay 20. Relay 26 opens the circuitleading to the windings of the pulse-generating relay 21 to prevent thisrelay from producing impulses.

When the calling subscriber manipulates his dial to transmit the seriesof impulses representing the first digit of the called number, namelythe digit 9, the impulse relay 4 releases and reoperates in response toeach of these impulses. On the iirst release of relay 4 a circuit isclosed from ground through the lower armature and back contact of saidrelay, front contact of relay 20, conductor 34 and thence in parallelthrough the windings of slow-release relay 35 and magnet I4 to battery.At the end of the rst irnpulse relay 4 reoperates, and magnet I4deenergizes to step brushes 6, 1, 8 and 9 to the next position. In likemanner the switch S--3 advances in response to each succeeding impulse'of the series and nally comes to rest at the end of nine steps inposition I2. In this position brush 6 engages the terminal 36. Relay 35energizes in the circuit above noted and, being slow to release,maintains its armature operated throughout the impulse series.

As soon as the register switch S--4 takes its first `step in response tothe rst impulse, the previously traced circuit for relays 23 and 22 isopened, and these relays release after an interval. Relay 22 closes acircuit from battery through the front contacts of relay, winding ofrelay 38, contacts of relay 22, closed contacts of relay 39, resistance4D to ground on conductor 28. Relay 38, however, does not operate atthis time since direct battery potential is connected to its winding byway of the closed left contact of the pulsing relay 21, normal contactsof relay 38 and the contacts of relays 39 and 22. When relay 23releases, as above noted, it opens the operating circuit of relay 26 andthis latter relay releases after an interval.

Relays 23 and 36 measure an interval between the commencement of theincoming impulse series and the closure of the operating circuitforrelay 21 to commence the outgoing impulse series. The purpose of thisinterval is to enable the selector switches to perform their trunkhunting operations between digit series. The operating circuit for relay21, which is closed as soon as both relays 23 and 26 have released, maybe tracedfrom battery through the upper or operating winding of relay21, normal contacts of relays 26 and 23 to the grounded conductor 28.The operating winding of relay 21 tends to move the armature from itsleft to its right contact but is delayed in doing so by the biasingwinding` of the relay, whiclris energized by charging current flowing tothe condenser 4I. As soon, therefore, as the assent@ '38 operates in thecircuit above traced. Also, re-

lay 21 in closing its right contact prepares an obvious dischargecircuit for condenser 4| through the resistance 42. As the condenserbecomes discharged, current increases in the-biasing winding (theinterval being measured by the resistance 42) in such a direction thatthe armature is shifted to its left contact. The engagement of thearmature with its left contact results in a circuit from battery throughthe armature and front contact of relay 38 to the winding of relay 39.This circuit causes the shunting of relay 30, which releases and opensthe impulsing circuit extending tothe selector S-I. Relay 38 remainsenergized in a circuit from battery through the armature and leftcontact of relay 21, normal contacts of relay 3D, winding of relay 38through the contacts of relays 22 and 39 and through resistance 49 tothe grounded conductor 28. When the impulse relay 21 again attracts itsarmature to its right contact,

the energizing circuit of relay 3B is opened, and

this relay releases. The next release of relay 21 to its left contactcloses the original energizing circuit of relay 39, and the latter relayoperates to reclose the impulse circuit. This cycle of operationscontinues, and measured impulses are transmitted over the conductors 3|and 33 to operate the selector switch S-L For each one of these impulsesover the outgoing circuit, relay 38 operates and closes an obviouscircuit over conductor 43 to operate the stepping magnet I5 of thecounting switch S-4. Switch S-4 takes a step with each impulsetransmitted and therefore reaches position I2 upon the transmission ofthe lastl or ninth impulse for the rst digit of the called subscribersnumber.

1n the meantime the register switch S-3 has already reached position I2in response to the incoming series of impulses; and, if the callingparty is prompt in transmitting the second digit, the register switchwill have advanced out of position I2 before the counting switch reachesthis position. Assume this to be the case, namely, that the secondseries of incoming impulses for the second digit 9 commences before therst outgoing series has been completed. Following the completion of thefirst series of incoming impulses, relay 35 released to close the tubeionizing circuit for marking the twelfth position of the register switchS-3. This circuit may be traced from the positive pole of battery 65,resistance 44, closed contacts of relay 22, this relay being deenergizedat this time, front contacts of relay, 29, back contacts of relay 35,conductor 45, brush 6, terminal 36 through the ionizing gap of tube 46to ground. Although this ionizing circuit is closed when relay 35releases, the tube is not discharged, since a short circuit is closed atthe front contacts of impulse relay 4. As soon, however, as the firstimpulse of the succeeding series is received, relay 4 opens its contactand removes ground potential from the ionizing circuit, whereupon thetube 46 is immediately discharged. Although this discharge circuitextends through the back contact of relay 35, the tube has ample time toionize its control gap before relay 35 attracts its armature to open theionizing circuit. The discharge tube 46 is held in an ionized conditionover a circuit extending from the positive pole of the anodeA battery41, resistance 48, through the anode and cathode of the tube 461:ground.

When, therefore, the counting switch S-v-4 reaches position I2 at theend of the first outgoing series of impulses, it finds the positionmarked by the discharged tube. This marked condition is detected by theoperation of relay 49 in a circuit from the positive pole of battery 10through the Winding of the relay, back contacts of relay 2'6, normalcontacts of relay 50, condenser 5|, brush I0, terminal 52 through thedischarged tube 46 to ground. Relay 49 'operating in this circuit closesa circuit from battery through its contacts, normal contacts of relay2'6, winding of relay 39 to ground at the front contacts of relay 20.Relay 39 opens thev circuit of relay 36 to prevent further stepping ofthe switch S-4. Subsequent operation of relay 30, as above described,operates relay 23, the circuit extending through the contacts of relay39 to ground at the contacts of relay 39. Relay 23 renders the pulsegenerating relay 21 ineffective and also reoperates relay 26. Thustheimpulse generating mechanism is disabled at the termination of theoutgoing series, relay 21 maintains its armature on its back contact,and relay 30 is operated and locked as above ldescribed to lhold theoutgoing loop closed. When relay 49 operates as above noted, it closesan obvious Vcircuit for relay 50, which opens the circuit of relay 49and places ground potential on conductor 5I. With ground potential onthis conductor a shunt circuit is closed through resistance 48 to quenchthe tube 46. Relay 49 being slow to release releases its armature afteran interval and opens the circuits of relays 39 and 59. Relay 39 opensthe energizing circuit of relay 23; and, since the original energizingcircuit of this relay through the brushes I2 and 8 is still open, theswitch S-3 having resumed its operation in response to the second digit,the relay releases after an interval and causes the release of relay 26.The release of these two relays measures the pause between the first andsecond digits, giving the switch S-I time to perform its trunk-huntingoperation. f

With relays 23 and 23 released, the pulsing relay 21 becomes effective,and outgoing impulses are transmitted for the second digit of the calledsubscribers number. In the meantime, the register switch S-3 advancesnine steps in response to thevsecond series of incoming impulses andcomes to rest in position 2|, that is, with its brush 6 resting onterminal 69.

The calling subscriber, continuing to dial, next transmits a singleimpulse representing the third digit of the wanted number, and theregister switch takes a single step as explained and comes to rest inits zero position, namely, with brush 1 in engagement with terminal 56.When relay 4 releases in response to this single impulse, the tubeionizing circuit becomes effective, and tube 53 is fired The energizedtube locks in its anode circuit, which extends from battery 41 throughresistance 54. When, a moment later, the counting switch S--4 reachesthe twenty-rst position, relay 49 operates over the circuit previouslytraced by way of conductor 5|, brush I0, thence over terminal 55 throughthe discharged tube 53 to ground. Relay 49 causes the cessation of theoutgoing impulses for the second digit, and relay 50 operates asexplained to quench the tube 53.

Finally the calling party transmits a series of three impulsesrepresenting the last digit of the number, and the register switch S-3advances to its fourth position, namely, with the brush 1 engagingterminal 51. On 'the first impulse 'of the last series relay 4remove'sgroundfrom 'the tube-firing circuit, and this circuit becomeseffective to ionize the tube 58, which is connected to the zero positionterminal 56 associated with brush The tube 58 is held energized by meansof a circuit from the positive pole of battery 68, resistance 60 throughthe anode and cathode of tube 58 to ground.

After the inter-digital pause is measured between the second and thirddigits of the number, the impulse mechanism becomes eiective to transmita single outgoing impulse to the connector switch C, and the countingswitch S-4 takes a single step bringing its brush into engagement withthe zero position terminal 59. Relay 49 operates in the circuit abovetraced over conductor 5| through brush and terminal 59 and thence toground through the tube 58. Relay 49 terminates the transmission of thethird digit and causes the quenching of tube 58.

In the meantime the register switch S-3 advances as above noted inresponse to the last digit and comes to rest in position 4. Here itremains, since no further impulses are transmitted from the callingline. After the interdigital pause between the third and last digits ofthe number, the impulse generating mechanism commences the transmissionof the last series of impulses to the connector switch C, and thecounting switch S--4 steps in synchronism therewith until it reachesposition 4. When the counting switch reaches position 4, it does notencounter a red tube, since the impulse relay 4 remains operatedfollowing the last digit and maintains the tube-firing circuitineffective. However, the switches S--3 and S--4 are now standing in thesame position at the end of the last digit, and the energizing circuitfor relays 23 and 22 is closed when relay 30 operates. This circuit istraceable from battery through the winding of relay 23, front contact ofrelay 3D, conductor 24, brush I3, terminal 6|, terminal 62, brush 9,conductor 25, Winding of relay 22 to ground at the armature and contactof relay 28. Relay 22 opens the circuit of relay 38 to prevent furtherstepping of the switch S4, and relay 23 releases relay 26 as abovedescribed.

In the foregoing description it was assumed that the calling subscribercommences the dialling for each succeeding digit before the countingswitch S-4 reaches the position marked by the register switch 5 3 forthe preceding digit. In this case the positions taken by the switch S-3at the end of each succeeding impulse series are marked by firing thetubes, excepting the last digit, and the counting switch S-4 detectsthese marked positions by operating the detect ing relay 49 when itreaches them. Relay 49 serves to disable the impulse generatingmechanism and to quench the red tubes. In the case of the last digit thetube corresponding to the position reached by the register switch S-3 isnot red, since the ionizing circuit is disabled, and the arrival of thecounting switch in the final stopping position of switch S-3 is detectedby the operation of relay 22, the circuit of which is closed wheneverboth switches S-3 and S-4 are standing in the same position. Relay 22,in operating, likewise disables the impulse generating mechanism toprevent the transmission of further impulses and to prevent stepping ofthe counting switch. It is possible, however, that the callingsubscriber may delay the transmission of each succeeding digit until thecounting switch S-II has reached the stopping position of the Vregisterlswitch S'3 for the preceding digit.

If so, the stopping positions of switch S-3 are detected in the mannerabove described for the last digit of a number.

When the connection is completed through to the called line 3 and thecalled subscriber answers, current is reversed over the conductors 3|and 33 in the well-known manner, and polarized supervisory relay 32operates. Relay 32 operates relay I6, which in turn reverses thedirection of current flowing over the trunk T to the originating office.This current reversal serves in the well-known manner to operatesupervisory apparatus in the calling office.

When the subscribers replace their receivers at the end of conversation,relays 4, 32 and I6 release. Relay 4 also causes the release of relay2U, which in turn releases relay 23. Relays 22 and 2| now operate in thecircuit herein-before traced and remain operated until the repeater istaken for its next use.

Should the repeater be released while the switches S-3 and S--4 are outof synchronism, that is, while these switches are occupying dilerentpositions, a circuit is prepared for automatically moving the countingswitch S-4 back into synchronism with the switch S-3. This circuit maybe traced from battery through the winding and contacts of magnet I5,conductor 63, through the back contacts of relays 2| and 28 to ground.As soon as switch S-4 reaches the position occupied by switch S-S, thepreviously-traced circuit is closed and relay 2| operates to open thstepping circuit of magnet I5.

While the invention is disclosed in an incoming impulse repeater it isequally applicable to outgoing repeaters. Also, these repeaters may beused in various types of systems and are not limited to the particularsystem illustrated herein. Furthermore, lit will be apparent thatvarious types of discharge tubes may be used for marking the positionsin the register and counting switches. For instance, tubes of thewell-known two-element type may be employed if desirable.

What is claimed is:

l. In a telephone system, a repeater comprising a register switch forregistering a series of incoming impulses, an impulse transmitter forgenerating and transmitting a series of outgoing impulses, a countingswitch for counting a series of outgoing impulses, means controlled bysaid impulse transmitter for operating said counting switch, a series ofdischarge tubes for the successive positions of said switches, each tubehaving its electrodes connected to the corresponding position terminalsof both said switches, means effective following the completion of animpulse series to discharge one of said tubes to mark the position towhich said register switch was `set in response thereto, and meanscontrolled through the discharged tube and a terminal of said countingswitch to terminate the series of outgoing impulses when said countingswitch is advanced to the position corresponding to the position takenby said register switch.

2. In a telephone system, a repeater comprising a register switch, meansresponsive to a plurali-ty of successive incoming impulse series foradvancing said switch progressively over its terminals in acorresponding number of consecutive movements to register said impulseseries, a counting switch for counting the successive series of outgoingimpulses corresponding to said incoming series, an impulse mechanism forgenerating and transmitting said outgoing impulses,

a series of discharge tubes for the successive positions of saidswitches, each tube having its electrodes connected to the correspondingposition terminals of both switches, means eiective after each impulseseries for discharging a tube to mark the position assumed by saidregister switch, and meanseiective when the counting switch reaches eachmarked position for disabling the impulse generating mechanism and forstopping the advance of said conuting switch.

3. In a telephone system, a repeater comprising a register switch, meansresponsive to a plurality oi' successive incoming impulse series foradvancing said switch progressively over its terminals in acorresponding number of consecutive movements to register said impulseseries, a counting switch for counting the successive series of outgoingimpulses corresponding to said incoming series, an impulse mechanism forgenerating and transmitting said outgoing impulses, a series ofdischarge tubes for the successive positions of said switches, each tubehaving its electrodes connected to the corresponding position terminalsof both switches, means effective after each impulse series fordischarging a tube to mark the position assumed by said register switch,means effective when the 'counting switch reaches each marked'p-ositionfor disabling the impulse generating mechanism and for stopping theadvance of said counting switch, and timing means for measuring aninter-digital pause between successive movements of said countingswitch.

4. In a telephone system, a repeater comprising a register switch forregistering a series of incoming impulses, an impulse transmitter forgenerating and transmitting a series of outgoing impulses, a countingswitch for counting a servies of outgoing impulses, means controlled bysaid impulse transmitter for operating said counting switch, a series ofdischarge tubes for the successive positions of said switches, each tubehaving its electrodes connected to the corresponding position terminalsof both said switches, means effective following the completion of animpulse series to discharge one of said tubes to mark the position towhich said register switch was set in response thereto, means controlledthrough the discharged tube and a terminal of said counting switch toterminate the series of outgoing impulses when said counting switch isadvanced to the position corresponding to the position taken by saidregister switch, and means controlled by said counting switch forrestoring each discharged tube to normal as soon as the counting switchhas reached the position marked by such tube.

5. In a telephone system, a repeater comprising a register switch forregistering a ser-ies of incoming impulses,4 an impulse transmitter forgenerating and transmitting a series of outgoing impulses, a countingswitch for counting a series of out-going impulses, means controlled bysaid impulse transmitter for operating said counting switch, a pluralityof gas-filled tubes having their control elements connected respectivelyto terminals of said register switch and having their cathodes connectedto a source of potential, means operative after the receipt of saidincoming impulse series to apply a potential to the control element ofone of said tubes to cause said tube to fire to mark the position towhich said register switch was set in response thereto, and meanscontrolled over the conducting path through said fired tube and a bankterminal of said counting switch to terminate the series of outgoingimpulses when said counting switch is advanced to a terminal positioncorresponding to the set position of said register switch.

6. In a telephone system, a repeater comprising a register switch forregistering a series of incoming impulses, an impulse transmitter forgenerating and transmitting a series of outgoing impulses, a countingswitch for counting a series of outgoing impulses, means controlled bysaid impulse transmitter for operating said counting switch, a pluralityof gas-iilled tubes having their control electrodes connectedrespectively to bank terminals of said register switch, having theiranodes connected respectively to corresponding bank terminals of saidcounting switch and having their cathodes connected ,to a source ofpotential, means operative after the termination of said incomingimpulse series to apply ground potential to the control electrode of oneof said tubes to cause said tube to fire to mark the position to whichsaid register switch was set in response thereto, and means controlledover the cathode-anode circuit of said fired tube to terminate saidseries of outgoing impulses when said counting switch is advanced to theterminal thereof to which the anode of the fired tube is connected.

ORFEO CESAREO.

ROBERT O. RIPPERE.

